Tables

FOREWORD

1. The Central Index of Dose Information (CIDI) is the Health and Safety
Executive's (HSE's) national database of occupational exposure to ionising
radiation. It is operated by the National Radiological Protection Board (NRPB)
under the terms of an extramural contract let by HSE.

2. The purpose of the CIDI database is to provide lifetime dose record
keeping continuity for employees that, at some time in their working lives,
have been designated by their employer(s) as a 'classified person' under
regulation 20 of the Ionising Radiations Regulations 1999 (IRR99) or regulation
9 of the Ionising Radiations Regulations 1985 (IRR85). Statutory instrument
IRR85 was revoked by the coming into force of IRR99 on 1st January 2000.

3. The CIDI database is kept up-to-date by annual dose summaries submitted
by Approved Dosimetry Services (ADS). Employers who designate classified persons
must make arrangements for their ADS to provide this information to HSE (and
therefore CIDI) in order to comply with regulation 21 of IRR99 (previously
regulation 13 of IRR85).

4. This document is the seventeenth published summary of CIDI annual statistics.

5. All data provided to HSE by ADS for inclusion in the CIDI database are
treated as confidential in respect of individual persons and employers.

6. The data referred to in this document are as held on the CIDI database
on 1 August 2003.

7. This publication may be freely reproduced and distributed for non-commercial
purposes provided that HSE is acknowledged as the source.

INTRODUCTION

1. The HSE Central Index of Dose Information (CIDI) receives annual summaries
of radiation doses recorded for employees designated as classified persons
under the Ionising Radiations Regulations 19991 (IRR99). These
annual summaries are required from Approved Dosimetry Services (ADS) which
operate in the United Kingdom under IRR99. Separate information is also sent
to CIDI by an ADS whenever an employee’s employment ends.

2. Approval to make assessments of doses to classified persons and/or to
keep records of such assessments is granted to suitable dosimetry services
by HSE. It is a condition of approval for dose record-keeping that annual
dose summaries are sent to CIDI, thereby fulfilling the statutory duty on
employers to make arrangements with their ADS to send such data to HSE. The
most common form of dose assessment is from measurements made by an external
body dosemeter of the thermoluminescent (TLD) or film type. An ADS may be
approved for other kinds of measurement however, such as bio-assay, whole
or partial body monitoring for internal radionuclides and personal or static
air monitoring. The resulting assessments of dose are included in dose records.

PURPOSE

3. CIDI has several functions:

A) to enable statistical analysis of employee radiation exposures in the
UK;

B) to provide an index that shows which ADS is, or has been, responsible
for the dose record keeping of a classified person and to act as a data back-up
for dosimetric information held by the ADS for such a person;

C) to enable annual verification of the number of classified persons designated
in the UK so that new registrations and terminations can be checked for consistency
with the previous year;

D) to act as a link between the old and new ADS when a person changes their
employer. This may, in exceptional cases, include relaying subsequently revised
data to the current ADS .

BACKGROUND

4. CIDI was established on 1 January 1987. The functions and operation of
CIDI are described in the Report of the Working Party on the Central Index
of Dose Information (NRPB-M92) 2 and associated Reference Manual
(NRPB-M176) 3.

5. The first year for which data were required was 1986. Since this date,
annual summaries have been published but only those for the last five years
are available on the HSE web site 4-8. This annual summary is
the sixteenth in the series, copies of summaries published before 1997 can
be obtained from the CIDI secretariat. It is intended that separate
reports will be published periodically on trends in annual statistics, such
as that covering dose data recorded for the years 1986 to 1991 9
and a second report covering the period 1990 to 1996 10.

6. The occupational categories used in the presentation of CIDI data are
given in HSE's published requirements for dosimetry service approval
11. Where more than one of these categories is applicable, a single
category is selected that refers to the largest proportion of the dose.

7. The number of classified persons for whom records were kept in 2002 was
41056.

TABLE CONTENTS

8. The specification of the information required in 2002 for CIDI purposes
is given in HSE'spublished requirements for dosimetry service
approval 11.

9. The data in the tables are as reported to CIDI by ADS; no changes, additions
or deletions have been made. Table A2 is an additional table derived from
Table A1 by substituting pro-rata dose estimates for notional doses.

10. The data within the various dose ranges of the tables are expressed in
millisieverts (mSv). Mean and collective dose within the tables are rounded
to the nearest 0.1 mSv and 1 man millisievert respectively. Values given as
a percentage are rounded to the nearest 0.1% (1% in Table B1). The data are
presented in a style similar to that of previous annual summaries.

11. This section presents the main dose information in terms of occupational
category and whole-body ionising radiation dose. The dosimetric quantities
used are effective dose Eext for external exposure and committed
effective dose Eint for exposure arising from intakes of radionuclides.
The data for the neutron component of Eext and the Eint
component arising from exposures to radon-222 and its short-lived daughters
are tabulated separately.

DOSE ESTIMATES AND NOTIONAL ENTRIES

15. Where no assessment of dose is available for any period of work as a
classified person, an estimation of the dose for that period must be made
by the employer and entered in the record in lieu of an assessed dose. No
distinction is made in the data between assessed and estimated doses. If there
is insufficient information upon which to make a dose estimate, the employer
must authorize the ADS to enter a notional dose in the record for that period.

16. The data in this summary include doses for classified persons who were
monitored for only part of the year or who changed their employment in radiation
work during the year. For such persons, there will be more than one dose summary
on CIDI for the year. A special check for such ‘double’ entries is therefore
made during the preparation of the data presented in this summary. Table A8
shows the number of persons monitored and the mean of their reported doses
in 2002.

17. The data submitted by ADS contain a relatively small fraction of notional
doses. Notional doses are substitute dose values in the record of a person
for a period when no dose assessment was available; they are based on the
proportion of the relevant annual dose limit for that period. Table A1 includes
notional doses. However, such values are rarely representative of the likely
doses to persons. For that reason a pro-rata dose estimate for the period
of each notional dose has been calculated by the CIDI statistics programme;
these data are presented in Table A2. The pro-rata dose estimate is based
on the doses assessed for the person during the rest of the year. This is
a well established convention in the presentation of dose record data and
one which gives a more realistic substitute dose value for dose analysis and
epidemiological purposes. This substitution applies only to the data during
their statistical analysis by CIDI and is not applied to the basic data on
the CIDI database or to the source data kept by the ADS: these remain unchanged.

DOSES ARISING FROM INTAKES OF RADIONUCLIDES

18. The CIDI protocol does not require submission of organ/tissue dose data
if doses are less than 10% of the pro-rata dose limit. Nevertheless, some
ADS have reported doses below this level and these have been included in the
tables. This means that there may appear to be discrepancies between certain
tables (e.g. Tables A5 and C7-C9).

19. Zero dose categories shown in the Tables, include both monitored classified
persons, for whom no measurable dose was recorded in the year, and persons
who were not monitored but who were reported as having received no measurable
dose as classified persons.

20. In Table A3, which shows neutron doses, the zero dose category also includes
zero neutron doses reported to CIDI by ADS for individuals who were not monitored
for neutron dose.